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Alpha channel is ignored for grayscale PNG
Posted: Tue Apr 14, 2009 8:37 am
by MaxSt
Examples:
XnView only displays alpha channel for the color image, not for the grayscale one.
Re: Alpha channel is ignored for grayscale PNG
Posted: Tue Apr 14, 2009 7:38 pm
by Clo
MaxSt
Hello ! Welcome aboard !
• I can confirm that there's an issue ! Here, it's displayed as a full black square,
and shown as “8 BPP” in the status bar…
• This image is shown correctly in some other viewers, though, i.e.
Imagine and
Universal Viewer…
Kind regards,
Claude
Clo
Re: Alpha channel is ignored for grayscale PNG
Posted: Tue Apr 14, 2009 9:00 pm
by XnTriq
Re: Alpha channel is ignored for grayscale PNG
Posted: Wed Apr 15, 2009 7:21 am
by xnview
Yes, currently xnview doesn't support alpha for greyscale
Re: Alpha channel is ignored for grayscale PNG
Posted: Wed Apr 15, 2009 7:36 pm
by MaxSt
Too bad. I hope it can be fixed. PNG is a very common format, it should be supported 100%.
I mean, XnView even reads animation chunks in png, surely reading alpha channel isn't much harder to implement.
Re2: Alpha channel is ignored for grayscale PNG
Posted: Wed Apr 15, 2009 7:59 pm
by Clo
MaxSt
Hello !
• In fact, the Alpha channel IS supported, but when the pics contain colours hues,
not only grey ones, it seems…
- Since your pic has an A-channel, it might be processed as any 32 BPP PNG -like in other viewers- no matter whether there are colours hues or only grey ones.
Pierre, please ?
KR
Claude
Clo
Re: Alpha channel is ignored for grayscale PNG
Posted: Tue Nov 03, 2009 6:27 am
by MaxSt
Bump?
I'm very happy with all the PNG improvements in 1.97b1, but there is one basic PNG feature left - mode 4 (grayscale+alpha).
PNG mode 4 is still not supported by XnView.
Re: Alpha channel is ignored for grayscale PNG
Posted: Tue Nov 03, 2009 7:50 am
by xnview
MaxSt wrote:PNG mode 4 is still not supported by XnView.
Yes, i've tried but need a lot of changes... So for the next time perhaps
Re: Alpha channel is ignored for grayscale PNG
Posted: Sat Aug 28, 2010 12:12 am
by ZoNi
Maybe you can somehow use Win Picture Viewer as "engine" for this?
Re: Alpha channel is ignored for grayscale PNG
Posted: Fri Mar 16, 2012 9:30 am
by x2088
can finish it?
Re: Alpha channel is ignored for grayscale PNG
Posted: Fri Mar 16, 2012 7:08 pm
by MaxSt
It's much worse now.
See:
Only the 1st of the 2 animations is working.